The invention relates to absorbent products including tampons, sanitary napkins, wound dressings and the like which absorb body fluids like menstrual fluid, blood, and wound exudates. The specific invention involves the determination of the preferred location of fatty acid esters such as glycerol monolaurate (“GML”) on the cover of the product and/or 10% of the fiber to result in a product which delivers a reduction in toxin production by microorganisms utilizing significantly lower concentrations of additive than that described in U.S. Pat. No. 5,641,503.
Direct addition of GML to fibers results in undesired increases in measurable solvent-extractable compositions and foaming.
The published prior art reports the potential use of a surfactant, GML, as a fiber finish for tampons in multiple patents including U.S. Pat. Nos. 57,532,522, 5,679,369, 5,705,182, 5,641,503, and 5,389,374. All patents describe the addition of GML to tampons to reduce the production of toxins from Staphylococcus aureus (“S. aureus”) as well as other bacteria including Strept. spp. The uniqueness of GML as an additive to tampons is that GML solubility in water is much less than 10% and thus remains coated on the tampon materials to provide a continued benefit. Thus, GML can be retained on the fiber as compared with other known fiber finishes which are water soluble and therefore, any preferential location of the typical fiber finishes to the tampon would result in the finish immediately washing away because of the total solubility of the surfactant finishes. Further, the fact that GML is able to reduce the TSST-1 production without significantly affecting the viability of S. aureus would suggest that GML addition to the tampon would not disrupt the normal flora of the vaginal vault.
Utilization of GML on fibers and/or covers in the aforementioned patents describe by example a minimum of 0.1% GML being added to the tampons. The patents describe simple pipeting onto the surface of the tampons without describing the potential benefits of uniformity, minimizing add-on and location of GML to allow for the beneficial effect of GML on S. aureus toxin production while allowing the product to have reduced extractables and foaming. The patents do not describe how to add GML in an effective concentration onto the absorbent structure (either absorbent core or cover) while providing desirable uniformity and a level of efficacy while still allowing for the beneficial effects of GML against toxin production by bacteria.
Addition of GML to the cover only and/or addition to only 10% of the fiber results in significant reduction in TSST-1 production by S. aureus. TSST-1 has been reported as the toxin responsible for Toxic Shock Syndrome which is a serious condition associated with tampon use.